Which ab exercise is better?

To be honest the best answer I got for this is nether. Get a mirror and and look at yourself from the side. Put your hand over your lower abs and suck it in as much as possible then take your hand off. Do this for 60 secs or for as long as you can. Trust me you will feel it Running helps to. Breathing alone works out your abs. Also a proper diet VERY important and a protean drink wont hurt. Hope this helps. :)